Mistakes were made. On that, everyone can agree with respect to the $25,000 contribution made to a political campaign group by the Donald J. Trump Foundation.

But the "how?" and the "why?" surrounding the mistake remain questions.

Here's what we know.

In 2013, a political campaign group tied to Florida Attorney General Pam Bondi's re-election campaign, And Justice For All, received a $25,000 check from the Donald J. Trump Foundation. The contribution was not properly reported on the Foundation's tax form, a 990-PF. Specifically, at VII-A, Statements Regarding Activities, the Foundation answered "no" to question 1a: "During the tax year, did the foundation attempt to influence any national, state or local legislation or did it participate or intervene in any political campaign?" According to the instructions for the form 990-PF:

"Political purposes" include, but are not limited to, directly or indirectly accepting contributions or making payments to influence the selection, nomination, election, or appointment of any individual to any federal, state, or local public office or office in a political organization, or the election of presidential or vice presidential electors, whether or not the individual or electors are actually selected, nominated, elected, or appointed.

Additionally, at Part VII-B, Statements Regarding Activities For Which Form 4720 May Be Required, the Foundation answered "no" to question 5a (1): "During the year did the foundation pay or incur any amount to [c]arry on propaganda, or otherwise attempt to influence legislation?"

The questions at Part VII-B are intended to determine whether there is any excise tax due. Under section 4955 of the Tax Code, a section 501(c)(3) organization must pay an excise tax "equal to 10 percent of the amount thereof" for any amount paid or incurred on behalf of or in opposition to any candidate for public office. The organization must pay an additional excise tax if it does not correct the expenditure timely. And, per the statute, "The tax imposed by this paragraph shall be paid by the organization."

That same year, the Foundation detailed contributions worth nearly $1 million to a variety of charitable organizations including the American Civil Liberties Union (ACLU) Foundation of Florida, the Make A Wish Foundation, and the Ronald McDonald House. The Foundation did not list the $25,000 donation to the Pam Bondi-related "And Justice For All" located in Florida but did list a donation for $25,000 to "Justice For All," a charity in Kansas; the Foundation, however, did not make a donation to the Kansas-based charity.

Florida Attorney General Pam Bondi speaks before the arrival of Republican presidential nominee Donald Trump during his campaign event at the Ocean Center Convention Center on August 3, 2016, in Daytona, Florida. (Photo by Joe Raedle/Getty Images)

The mistakes on the return might have gone unnoticed except for the timing.

The check to the Bondi-related committee in the amount of $25,000 was dated September 17, 2013. Three days before, the Orlando Sentinel had published a story alleging fraud at Trump University. Subsequently, Florida Attorney General Pam Bondi announced that she would not investigate allegations of fraud against Trump University citing a lack of complaints. You can read Orlando Sentinel reporter Scott Maxwell's story about those allegations - and his efforts to get more information - here.

While Florida's Attorney General declined to pursue the case, New York's Attorney General did not. New York's Eric Schneiderman moved ahead, filing suit against the now-defunct organization. The suit is now moving ahead. This year, Schneiderman defended the timing, saying, "We sued him in 2013. He says it's a political case. Nobody in August 2013 thought that this guy was going to be the Republican nominee for president."

An additional case against Trump University (one of two in the state seeking class action status) is proceeding in U.S. District Court in San Diego, California.

Trump has dismissed the allegations against Trump University and insists that the Bondi-related donation wasn't tied to the investigation in Florida, saying, "I never spoke to her, first of all. She’s a fine person, beyond reproach. I never even spoke to her about it at all. She’s a fine person. Never spoken to her about it, never. Many of the attorney generals turned that case down because I’ll win that case in court. Many turned that down. I never spoke to her."

It's not quite clear whether Trump was referring directly to the donation or the investigation. However, earlier this year, the Associated Press reported that Marc Reichelderfer, a consultant for Bondi's re-election campaign, declared that Bondi personally solicited the donation from Trump. However, Reichelderfer stressed that Bondi was not aware of the complaints against Trump University when she asked for the donation.

In 2016, when the donation to the Bondi group became public, Trump paid the 10% excise tax, or $2,500, to the Internal Revenue Service (IRS). Trump's chief financial officer told The Washington Post that paying the contribution out of Foundation funds and the subsequent failure to properly report the donation were the result of a series of mistakes made by clerks and the Foundation's accountants. Trump spokeswoman Hope Hicks told NBC that "[t]his was a minor issue that was brought to the attention of the Foundation and addressed immediately."

Critics, including the Citizens for Responsibility and Ethics (CREW) in Washington, believe that it looks like something more. Jordan Libowitz, a CREW spokesperson, says, at a minimum, that the donation should be returned. Nancy Watkins, who handles accounting for "And Justice For All" said she tried, telling the Post, "I wrote a check, sent it via FedEx. I received a call from the Trump Foundation, saying that they had declined to accept the refund."

The improprieties are serious enough, Libowitz says, that the IRS should investigate. His group made such a request directly to IRS Commissioner John Koskinen in March of 2016 and followed up with another request in August of 2016.

If that sounds familiar, Koskinen received a similar request to investigate the Clinton Foundation (which is a public charity and not a private foundation) earlier this year amid "pay to play" allegations. The Clinton Foundation has denied any wrongdoing with respect to those allegations. As is typically the case, the IRS has not directly addressed the allegations for either of the organizations.

Why, then, should taxpayers be concerned about allegations against private foundations? Libowitz says that evidence suggests that they are engaging in an increasingly "impermissible amount of politics." And that, he says, is clearly of interest to a lot of people. It's also the reason that we have public filings, he adds, noting that it provides transparency.

But as we're seeing, transparency can be tricky. That may be because the rules governing private foundations are complicated. Under current tax law, every tax-exempt organization under section 501(c)(3) of the Tax Code is considered a private foundation unless it's excluded. Excluded organizations are typically what you and I consider public charities because typically they either have broad public support or they actively support organizations that do. That distinction is important because a private foundation is usually funded or controlled, at least initially, by an individual or business.

Private foundations are subject to a number of restrictions and requirements. Those include restrictions on self-dealing between the foundations and their substantial contributors, a requirement that income is distributed each year for charitable purposes, and kind of a generic provision that expenditures must further exempt purposes. To ensure compliance with these rules, all private foundations must annually file a form 990-PF, Return of Private Foundation (downloads as a pdf). The form 990-PF is subject to public disclosure.

Additional rules and restrictions apply to taxpayers: in general, a taxpayer can deduct contributions to a public charity of up to 50% of his or her adjusted gross income (AGI) while a taxpayer can only deduct contributions to a private foundation of up to 30% of his or her AGI. That distinction can matter come tax time depending on the value of your gift. When making a donation to any charitable organization, it's a good idea to search the IRS database of charitable organizations using the Select Check Tool. You can confirm the charitable status, as well as deductibility limits. That's an important step because an organization may have the word "foundation" in the title even though it’s a public charity, as is the case with the Clinton Foundation:

Your best bet of private foundation status is confirmation from IRS, as is the case with the Donald J. Trump Foundation:

It's clear that Trump's camp considers the matter closed. Libowitz, however, says that his organization will continue to follow up because there are still unanswered questions. It's not political, he claims, and it is "not about who is attached to the donation." Instead, it's about the process. "There are rules," he says, "And there should be consequences when the rules are not followed."

Years ago, I found myself sitting in law school in Moot Court wearing an oversized itchy blue suit. It was a horrible experience. In a desperate attempt to avoid anything like that in the future, I enrolled in a tax course. I loved it. I signed up for another. Before I knew ...